1. Field of the Invention
The present invention relates to hydraulically-operated micromanipulator apparatus including microtools, such as a glass electrode positioned in the field of a microscope with the use of hydraulically-operated remote controlling means.
2. Prior Art
In basic medical science or biotechnology, micromanipulators are used for treating cells, such as creature's organs, cellular textures, egg cells and the like. These cells are treated in various operations for example suctioning, injecting and dividing by finely controlling a microtool in the field of a microscope.
However, when an operator finely controls the micromanipulator by his direct contact with its control handle, his hand trembling may be multiplied and transmitted to the microtool through the body frame. For this reason, care should be taken for finely controlling the micromanipulator. Since the micromanipulator needs to be gently operated without hand trembling, delicate operations, the greatest possible care and a lot of skills are required. In view of these difficulties, a various hydraulically-operated micromanipulators have been proposed for finely controlling the microtool by remote controlling means. These micromanipulators are controlled by hydraulic fluid, such as hydraulic oil.
Referring now to FIG. 1, a conventional cell treatment device comprising a stage 303 for mounting a Petri dish 302 containing therein egg cells 301 dipped in a reagent, a fixed retaining unit 304 for stationary retaining the cells 301, a micromanipulator 305 for carrying out a practical cell treatment, and an optical system 306 for observing images of the cells 301 irradiated with light. The cell treatment device is operated on a vibration-proof mat 307.
The micromanipulator 305 is attached with various kinds of microtools 308, such as a glass electrode for the corresponding cell treatments and includes a three dimensional displacement mechanism for moving the tip end of the microtool 308 in three dimensions. The three dimensional displacement mechanism is finely operated by hydraulic pressure through a joystick 309.
The joystick 309 comprises a control handle 311 downwardly extending from the distal end of a visor-shaped supporting frame 310 and a transmitting unit 313 for transmitting the two directional movement 312 of the control handle 311 shown by the arrows through hydraulic pressure. The control handle 311 is provided with a converting unit 314 for converting the two directional movement of the control handle 311 into a mechanical displacement in a horizontal plane. The converting unit 314 connects the supporting frame 310 and the control handle 311. For the vertical movement of the cells to be treated, another mechanism may be provided at an adjacent position of the joystick 309.
In other conventional device, the control handle extends upwardly from the converting unit 314. However, since the operator can operate the device at a lower position without raising his arm, the former type, i.e., the micromanipulator with downwardly extending control handle has been widely used.
However, in micromanipulators operable by hydraulic pressure, such as oil pressure or water pressure, when ambient temperature changes, the volume of hydraulic fluid may also change. This leads to drift of the tip end of the microtool, and hence accurate observation or operation is not achieved.
Other electrically-operable micromanipulator is also known. However, in such micromanipulator, the tip end of the microtool drifts when it is subject to electric hindrance. The problems relating to drift, therefore, remain unsolved.
Such problems are serious when a long period of observation or operation is carried out while the tip end of the microtool is abutting to a sample. When drift occurs, the tip end of the microtool moves off from the sample, and hence the observation or operation is interrupted.
With the foregoing drawbacks in view, the present invention seeks to provide micromanipulator apparatus, which are hydraulically-operable by remote controlling means and include means for compensating drift of the microtool due to a temperature change.